The present invention relates generally to vehicle supplemental inflatable restraint systems and, more particularly, to the interaction between the air bag module and an instrument panel or door panel during deployment of an air bag cushion.
Driver side or passenger side supplemental inflatable restraint (SIR) systems typically include an air bag stored in a housing module within the interior of the vehicle in close proximity to either the driver or one or more passengers. SIR systems are designed to actuate upon sudden deceleration so as to rapidly deploy an air bag to restrain the movement of the driver or passengers. During deployment, gas is emitted rapidly from an inflator into the air bag to expand it to a fully inflated condition.
Air bag passive restraint systems include an inflator, which produces gas to inflate the air bag cushion. Known inflators for air bag modules are generally of three types. One type is the pure gas inflator wherein a pressure vessel contains stored pressurized gas. The pressure vessel communicates with the cushion through various types of rupturable outlets or diaphragms. Another type is the gas generator wherein a propellant is ignited and the resultant gas created flows through an outlet to the cushion. A third type is the hybrid or augmented type. This type includes a pressure vessel containing stored pressurized gas and a gas generator. When the generator is ignited, the resultant gas flows with and heats the stored gas going to the cushion through the pressure vessel outlet.
Typically, the air bag module is mounted to a steering wheel hub or is disposed within another location in the vehicle, such as the instrument panel or a driver side or passenger side door. The air bag module is positioned relative to the instrument panel so that a relatively thin tear seam formed in the instrument panel is designed to tear open under the force of the air bag cushion, which is directed towards the tear seam. Because conventional air bag modules use the pressure generated in the air bag cushion to rupture the tear seam, the tear seam itself is relatively thin. The thinner the tear seam, the greater the likelihood that over time the tear seam may weaken.
This invention offers advantages and alternatives over the prior art by providing a deformable air bag module for use in an instrument panel or the like of a vehicle. The air bag module of the present invention is intended for use in passenger side (SIR) systems and also in side impact systems in which the air bag module is disposed in a door panel. Furthermore, the present invention may also be used in a seat mounted air bag assembly. The air bag module has a deformable module housing with an inflator and an air bag cushion being disposed within the deformable housing. The module housing has a neck portion defining an opening formed at a first end, wherein the first end is coupled to the instrument panel. More specifically, the instrument panel includes first and second instrument panel sections with retaining members being disposed on each of the first and second instrument panel members for retaining the module house thereto. The first end of the module housing preferably includes a flange which is received within the retaining members to securely couple the air bag module to the first and second instrument panel sections.
In one embodiment, the instrument panel includes a front and rear surface, wherein the rear surface includes a tear seam which defines the first and second instrument panel sections. The module housing is disposed about the tear seam so that the tear seam is aligned with the opening of the module housing. Under deployment conditions, the inflator generates inflator gas which inflates the air bag cushion. The inflating air bag cushion is directed toward the neck portion and the opening defined thereby and the expansion of the air bag cushion causes the neck portion to deform resulting in expansion of the module opening. This deformation of the module housing causes the first and second instrument panel sections to separate along the tear seam because the module housing is coupled to both the first and second instrument panel sections. The separating first and second instrument panel sections create a path for the air bag cushion to escape from the air bag module and deploy outwardly from the instrument panel.
In a second embodiment, the instrument panel has first and second instrument panel sections which abut one another. The module housing is disposed about the first and second instrument panel sections where the two sections abut one another so that the abutting portions of the first and second instrument panel sections are aligned with the opening of the module housing. Under deployment conditions, the inflator generates inflator gas which inflates the air bag cushion. The inflating air bag cushion is directed toward the neck portion and the opening defined thereby and the expansion of the air bag cushion causes the neck portion to deform resulting in expansion of the module opening. This deformation of the module housing causes the first and second instrument panel sections to separate because the module housing is coupled to both the first and second instrument panel sections. The separating first and second instrument panel sections create a path for the air bag cushion to escape from the air bag module and deploy outwardly from the instrument panel.
In a third embodiment, the instrument panel has first and second instrument panel sections with a panel opening formed therebetween. A swivable door is disposed within the panel opening. The module housing is disposed about the panel opening and door so that the panel opening is aligned with the opening of the module. During deployment conditions, the air bag module deforms due to the movement of the air bag cushion and this deformation causes the first and second instrument panel sections to separate along the panel opening because the module housing is coupled to both the first and second instrument panel sections. The separation of the first and second instrument panel sections causes the door to swing open and creates a path for the air bag cushion to escape from the air bag module and deploy outwardly from the instrument panel.
The air bag module of the present invention uses the natural forces (i.e. pressure build-up in the air bag cushion) and bell-mouthing of the housing advantaseously as a mechanical means rupturing the tear seam or separating the panel sections permitting deployment of the air bag cushion. Unlike conventional systems, the air bag cushion itself is not the primary member for causing the separation of the panel. In other words, the pressure of the air bag cushion contacting the panel is not the primary force to cause separation thereof. As a result, a thicker more durable tear seam may be used because the force which is intended to rupture the tear seam is not solely the pressure generated by the air bag cushion.
The above-described and other features and advantages of the present invention will be appreciated and understood by those skilled in the art from the following detailed description, drawings, and appended claims.